Esther and Gerald each investigated the effects of snake venom cream on arthritis symptoms. Separately, they both recruited volunteers and randomly divided them into two groups. Both of them administered snake venom cream to one group and a placebo cream to the other. Esther found that snake venom cream relieves arthritis symptoms, while Gerald found that it does not. Which of these statements is true?
Gerald performed an experiment because he randomly administered snake venom cream to some of the volunteers.
Gerald performed an observational study because he found that snake venom cream does not relieve arthritis symptoms.
Esther performed an observational study because she randomly administered a placebo cream to some of the volunteers.